NOOK Color eReader LCD Touchscreens

The screen on the NOOK Color eReader has three important attributes: it is a flat liquid-crystal display (LCD), it is capable of producing as many as 16 million subtly different colors, and it responds to the touch of a finger. Each of these attributes is a wonder unto itself, and together they make an amazing product.

The screen

LCDs have just about completely pushed aside the cathode ray tube for televisions and computer monitors, and they are the only way today’s laptop computers, smartphones, and GPS devices are possible.

The NOOK Color Home screen.

An LCD has a fast “refresh” rate, meaning that the individual points (called pixels) can be turned on or off quickly; this allows the display of video and other moving images. A typical rate might be 2 milliseconds, or 500 refreshes per second.

Although modern science has greatly reduced the amount of electricity needed for this package of technologies, it is nevertheless a fact that the backlight and the LCD are major consumers of battery power. Both need to be powered on to display letters or images. An LCD device can be read in a dark or dimly lit room, although the screen can be overwhelmed by light that is too bright, like the midday sun.

The NOOK Color allows you to turn down the brightness of its backlight, which will save a bit of battery power in some circumstances and may improve the performance of LCDs in bright daylight.

The colors

In the simplest terms, an LCD is made up of two transparent panels with a liquid crystal solution between them. A light shines from behind the display, and an electrical signal tells each tiny crystal whether to allow light to pass through or be blocked. Millions of these crystals, paired with tiny red, green, or blue filters, construct characters and images.

The touchscreen

The NOOK Color’s touchscreen adds the ability to sense the presence of a finger at a particular location or to pick up the motion of one or more fingers across the screen in any direction. The touchscreen substitutes for an onscreen cursor controlled by a mouse, a directional pad, or other pointing device.

One more thing: The NOOK Color does not display a screensaver, an image that replaces the reading material when the device is not in active use. Instead, to save precious battery power, the device will go to sleep and present a blank screen to the world. You can adjust the time lapse before the device goes to sleep in the Screen section of the Device Settings menu.